要开始开发项目了，在我参加之前，他们都比较关注技术细节，比如曲线，报表之类的，对于整个软件的体系结构基本没有考虑过，这令我比较奇怪。由于我有些java开发大型项目的经验，知道一个好的体系结构对项目开发的重要性。所以开始着手架构问题。

采用分层的体系结构，将用户界面、业务逻辑处理、数据访问、以及一些操作数据库必须的操作分离开来。

Business

Data

EntityClass

WinForm

层次如上所示。具体每一层里面的内容。

一、Data层

主要完成一些对数据库的基本的通用的 操作，包括两个文件，ConnectionFactory.vb和DataFactory.vb

ConnectionFactory.vb完成连接数据库的操作，代码如下：

Imports System
Imports System.Data
Imports System.Data.SqlClient
Namespace Data
    Public Class ConnectionFactory
        Private Const ConnectionKey As String = "ConnectionString"
        Public Sub New()
            ' TODO: 在此处添加构造函数逻辑
        End Sub
        Public Shared Function myConnection() As System.Data.SqlClient.SqlConnection
            Dim cmConn As New SqlConnection
            Dim strConnection As String = System.Configuration.ConfigurationSettings.GetConfig(ConnectionKey)
            strConnection = "server=200.200.200.101;database=winlog;user id=sa;password=sa"
            If strConnection <> " " Then

                cmConn.ConnectionString = strConnection
                Return cmConn

            Else
                '应该返回null
                cmConn.Close()
                Return cmConn
            End If
        End Function
        Public Shared Function myConnection(ByVal strConnection As String) As System.Data.SqlClient.SqlConnection
            Dim ConnectionKey1 As String
            If strConnection <> " " Then
                ConnectionKey1 = strConnection
            End If
            Dim cmConn As SqlConnection = New SqlConnection
            strConnection = System.Configuration.ConfigurationSettings.GetConfig(ConnectionKey1)
            If (strConnection <> "") Then

                cmConn.ConnectionString = strConnection
                Return cmConn

            Else
                cmConn.Close()
                Return cmConn
            End If
        End Function